1. Field of the Invention
The present invention relates to methods of labeling manufactured goods. More specifically, the invention relates to a method of labeling roofing shingles with information that is highly concentrated due to use of a binary coding scheme.
2. Related Art
For a variety of reasons, it is desirable to mark manufactured goods with tracking information. For example, in the roofing shingle industry, tracking information may include a slit that uniquely identifies the plant site at which a particular shingle was manufactured. Conventionally, the slit is made by passing an endless sheet of shingle material between a cutter head and an anvil roll, and a marker knife on the cutter head identifies the shingle as having been manufactured at that particular plant. Such tracking information allows a manufacturer to trace defective goods to a particular plant site, so that the defect can be investigated and remedied.
However, such simplistic labeling schemes provide little information. The bare identification of a plant site does not permit specific identification of a particular date on which a defect occurred, or the shift at that plant site that is responsible for the defect. This is a significant shortcoming when the defect occurs in only some of the shingles manufactured at the identified plant site, but not in other shingles manufactured at the same plant site. In this event, the cause of the defect cannot be localized or corrected, because the labeling system does not contain enough information to specify the exact location, date and shift of manufacture.
Thus, there is a need in the art to provide a method of easily providing enough information on manufactured roofing shingles so that the time and location of their manufacture can be quickly and uniquely determined, so that any manufacturing process defects can be isolated and corrected, and to provide information to defend against false warranty claims.